Heat Transfer and Fluid Flow Analysis of Molten Salt Heat Exchanger in a Novel Thermolysis Reactor Design for the Thermochemical Cu-Cl Cycle for Hydrogen Production
Date of Award
Mechanical, Automotive, and Materials Engineering
Copper oxychloride, Cu-Cl thermochemical cycle, Heat exchanger design, Hydrogen production, Molten CuCl, Thermolysis reactor
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Among the new methods for producing clean hydrogen, the thermochemical copper-chlorine (CuCl) cycle is one of the most promising due to the relatively high exergy and energy efficiencies and lower temperature requirements. However, there are challenges with regard to the thermal performance of the components of the cycle. This study focuses on designing a new heat exchanger for the thermolysis reactor, which is found to be the most critical component because of having the highest operating temperature, highest exergy destruction, and material handling difficulties. The objective is to provide the required operating temperature, of 430 to 530 °C, for the reaction inside the thermolysis reactor of a 4-step Cu-Cl cycle.
To design the heat exchanger, the required conditions for the thermolysis reaction are found. Then a heat exchanger design methodology is developed along with an algorithm for the sizing problem. Nine design cases resulted from the sizing problem, and three of them are selected for further evaluation of the thermal performance using a 3D numerical model. After comparing the performance of the three designed heat exchangers using five performance parameters, i.e., T*,TD, temperature effectiveness, pumping power, and thermal performance factor, one is selected for applying the performance improvement techniques. Two performance improvement techniques are used: 1. using two fin configurations inside the reactant channel and 2. manipulating the inlet temperature for the heating side. The final design for this study improved the heat exchanger temperature effectiveness and thermal performance factor by 15% and 138%, respectively. The T*for reactant side is decreased by 51% compared to the previous designs, and the reactant side TD is decreased by 61%.
Armoudli, Ehsan, "Heat Transfer and Fluid Flow Analysis of Molten Salt Heat Exchanger in a Novel Thermolysis Reactor Design for the Thermochemical Cu-Cl Cycle for Hydrogen Production" (2022). Electronic Theses and Dissertations. 8915.